Accelerated Partial Breast Irradiation with Iridium-192 Multicatheter PDR/HDR Brachytherapy

PURPOSE: To evaluate perioperative morbidity, toxicity, and cosmetic outcome in patients treated with interstitial brachytherapy to the tumor bed as the sole irradiation modality after breast-conserving surgery. PATIENTS AND METHODS: From November 1, 2000 to January 31, 2004, 176 women with early-stage breast cancer became partakers in a protocol of tumor bed irradiation alone using pulsed-dose-rate (PDR) or high-dose-rate (HDR) interstitial multicatheter implants. Patients became eligible, if their tumor was an infiltrating carcinoma < or = 3 cm in diameter, the surgical margins were clear by at least 2 mm, the axilla was surgically staged node-negative, the tumor was estrogen and/or progesterone receptor-positive, well or moderately differentiated (G1/2), the tumor did not contain an extensive intraductal component (EIC) and the patient's age was > 35 years. Implants were positioned using a template guide, delivering either 49.8 Gy in 83 consecutive hours (PDR) or 32.0 Gy in two daily fractions over 4 days (HDR). Perioperative morbidity, toxicity, and cosmetic outcome were assessed. Interim findings of the first 69 patients, who were treated in this multicenter trial, after a median follow-up of 24 months (range, 15-39 months) are presented. RESULTS: One of the 69 patients (1.4%) developed a bacterial infection of the implant. No other perioperative complications, for example bleeding or hematoma, were observed. Acute toxicity was low: 2.9% of the patients (2/69) experienced mild radiodermatitis. Late toxicity: hypersensation/mild pain 7.2% (5/69), intermittent but tolerable pain 1.4% (1/69), mild dyspigmentation 10.1% (7/69), mild fibrosis 11.6% (8/69), moderate fibrosis 1.4% (1/69), mild telangiectasia (< 1 cm(2)) 11.6% (8/69), and moderate teleangiectasia (1-4 cm(2)) 1.4% (1/69). Good to excellent cosmetic results were observed in 92.4% of the patients evaluated. All patients (n = 176) remained disease-free to the date of evaluation. CONCLUSION: This analysis indicates that accelerated partial breast irradiation with iridium-192 interstitial multicatheter PDR/HDR implants is feasible with low perioperative morbidity, low acute and mild late toxicity, and does not significantly affect cosmetic results at a median follow-up of 24 months.